PreVent® 3-Dimensional Bonnet Fan Guards Vent Caps Socks & Diffusers

Elastic Air Filter Frame
Elastic Frame Fan Guard Air Filter
Fan Guard
sonic welded air filter frame
Vent Cap

Protect equipment motors, workers and products from harmful airborne dust and contaminants with bonnet style, vent cap style, sock style and ceiling vent diffuser style equipment protection air filters. Available in a 3-dimensional styles for use on circular fan guards, vent fans, exhaust fans, or inlet or outlet vents to prevent possible contamination from dust, dirt, thread, lint, fibers and other irritating contaminates.

Buildings Money Saving Product

BUILDINGS magazine selected PreVent Fan Guard Filters as an HVAC Fix – 2016 Money-Saving Product winner. PreVent is part of an elite group of products showcased in the magazine’s June 2016 issue.

PreVent 3D Filters can be Customized

These custom air filters contain one layer of washable electrostatic polypropylene media, black or white in color, custom sewn with vinyl edging, elastic cloth binding or sonic welded edges to fit over any sized air inlet or outlet. Approximately 1/8″ thick, our PreVent 3-dimensional custom air filters can be made in any size diameter, including over-sized for extra-large outdoor HVAC equipment including vent fans, exhaust fans, and more.  A simple solution to protect your personnel, process, equipment and general air circulation.

Black polypropylene media is UV protected and can be used for outdoor applications. White polypropylene media is FDA approved for food processing applications and works well to meet AIB Food Safety audit and inspection dust collection and filtering device requirements. Additional media (nonwoven polyester or foam) can be added upon request to the filter configurations to increase arrestance efficiency. Pull tabs and drawstrings can be added for easy access or hook/loop closures for wrap around style filters.

PreVent 3D Styles Available in 5 Models:

  • Model BONNET fits over the circular front side of a fan guard grill to stop dust and dirt from blowing out into the environment. Available in black or white polypropylene with elastic edging.
  • Model FANGUARD fits over the circular back side of a fan guard grill to stop dust and dirt from being drawn into the fan, features a center motor cut-out and hook/loop closure. Available in black or white electrostatic polypropylene with elastic edging.
  • Model VENTCAP can be made square or rectangular to fit ceiling or wall vents, finished with an elastic edge to hold in place. Standard height is 4″, custom height available upon request. Available in black or white electrostatic polypropylene.
  • Model SOCK is a drop down design for ceiling vents or rooftop exhausts. Available in black or white electrostatic polypropylene with elastic edging.
  • Model DIFFUSER fits on a drop down ceiling vent diffuser held in place with a standard metal grid panel system. Vinyl edging contains magnetic attachment for easy installation and removal. Available in black or white electrostatic polypropylene. Flat faced vent diffusers can also be protected with our PreVent Model R filters with a rigid galvanized steel frame and magnetic stripping.

PreVent air filters carry a 5-year warranty (extended warranty is available upon request).


  • The order process went very well.  We received the black washable fan bonnets 2 weeks ago and are very happy.  I will order again in the future.   Great product and great service.  Thank You!

    Geoff DawesFestival Foods, Maintenance Tech. II
  • The PreVent bonnet style filter is the best thing I have ever bought to protect our cooling tower circular fan. We have to clean it every two weeks but it is so easy.

    Martyn RogersCotek Papers Limited, Maintenance Manager
  • Several of our large commercial buildings in Atlanta have purchased the PreVent filtering product for their cooling towers. The benefits of being able to get through our spring season without much intrusion into the building owners equipment has been successful. The product was easy to install and has been simple for the customers to maintain. We are excited to have this product in our line of filtration options.

    Joey ChapmanAir Filter Sales and Service, Inc.
  • I use the PreVent Model R filters with magnetic option that allows them to stick to the ironsteel surface of my Kaeser compressors, Kaeser air dryer and YASKAWA inverter on a Braun washer. I rinse with hot water once a week. These can be used in many applications and do save significant time for maintenancePM work. I also have installed this type filtration on all HVAC units. Easily eliminates 90% of lintdust that otherwise enters these areas

    Mark WearAramark Uniform Services, Oklahoma City, OK

Protect workers, products and equipment motors from harmful airborne dust and dirt with 3-dimensional bonnet, vent cap, sock or diffuser style equipment protection air filters.